Environment Canada’s new research suggests that climate change has increased the likelihood of catastrophic floods like those that flooded much of southern British Columbia last autumn.
The study, which is currently undergoing peer review, concluded that similar events will increase as global heating continues to disrupt normal weather patterns.
We do find significant ongoing increases in the likelihood of these events, according to Nathan Gillett, an atmospheric scientist and manager of Canada’s Centre for Climate Modelling and Analysis.
B.C. Three events came together to create unprecedented flooding.
Two days of torrential rain brought on by the atmospheric river. It fell on already-sodden soil, which couldn’t absorb more water, and was further exacerbated by high temperatures that swelled stream beds with snow melt.
The result was that almost 15,000 people were forced from their homes, major roads, bridges and roads were washed away, while farms were submerged in water up to two meters deep. At least five people died in landslides.
Insurance losses have been estimated to be $450 million. 600,000 chickens died and 12,000 hogs.
Gillett and his associates wanted to estimate the impact of climate change on the disaster while it was still fresh in the public’s memory. They turned to the science and art of climate attribution to estimate the impact of one or more variables on weather events.
He said that simulations with human influence were compared to simulations without human influence.
The team collaborated with an Oxford University group that was doing similar research. The team used over two dozen different models to ensure the results weren’t affected by quirks in any model. The results were consistent across them all.
All models show an increase in this type of event due to human-induced global warming.
The team concluded that climate changes had increased the chances of an atmospheric river, like the one that flooded B.C. By at least 60%
Gillett stated that there are higher chances of an atmospheric river event happening now than in the 19th century. There are now three events where there were previously two.
When scientists considered all the factors that contributed to the disaster, they concluded that B.C. had a good chance of it happening. Climate change had at least doubled the odds of what happened to B.C., and possibly quadrupled.
That’s just for the current climate that is already being affected by climate change. As greenhouse gases continue to enter the atmosphere, the chance of another catastrophe increases.
Gillett said that they expect this to rise as the climate continues its warm trend.
There is mounting evidence that climate change is already causing extreme weather and damage. Oxford researchers discovered that the heat dome brought unprecedented temperatures to B.C. Climate change would have made it impossible to create a wildfire that would have decimated Lytton.
Gillett stated, “The conclusions point to the necessity to rebuild roads and buildings that can withstand more severe weather than they did in the past.”
When rebuilding infrastructure, it is important to consider how these types of events are increasing and take that into consideration.
This report was first published by The Canadian Press on February 15, 2022.
